This invention relates generally to textiles and more particularly to stretch yarns and methods for making stretch yarn.
For certain types of clothing it is considered desirable to use fabrics exhibiting “stretch” properties, i.e. the ability to be extended under a relatively low force and to elastically return to the original shape and size. Stretch properties may be imparted by the type of fabric construction, such as knitting, and also by incorporating yarns which themselves have stretch properties.
It is known to make stretch fibers using urethane chemistry. One well-known stretch fiber is a polyester-polyurethane copolymer, sold under brand names such as SPANDEX. This fiber (in the form of a filament yarn) is often blended with or used alongside other fibers such as cotton or polyester to make fabrics and clothing. While effective to provide stretch properties, it has a high cost.
Accordingly, there have been attempts to make stretch yarns from other synthetics, in particular blends of bicomponent fibers comprising poly(ethylene terephthalate), also referred to as “PET”, and poly(trimethylene terephthalate), also referred to as “PTT”. Such fibers have a much lower cost that urethanes. However, these are still more expensive than cellulosic staple fibers (e.g. cotton) or other natural staple fibers. In the prior art it has been believed that relatively large amounts of such fibers are required to achieved adequate stretch properties in yarn.
Accordingly, there remains a need for a stretch yarn utilizing minimal amounts of synthetic fibers.